Saving parsed json to (and reading it back from) memory, e.g. in binary format

[Tom-Evers]

Take this very simple example:

json structure;
try
{
    std::ifstream i("layout.json");
    i >> structure;
}
catch (json::parse_error& e) { std::cerr << "Error parsing structure file\n" << e.what() << std::endl; }
catch (json::type_error& e)  { std::cerr << "Type error in structure file\n"  << e.what() << std::endl; }
catch (json::other_error& e) { std::cerr << "Other error in structure file\n" << e.what() << std::endl; }

The line i >> structure; parses the contents of layout.json into a json object called structure.

Is there any way for me to dump structure into some file that can be read directly back into a json object (i.e. without having to parse it)?

Ideally, I'd like a compile time solution. Something I can "include" directly. For example: I run the parser once and export the resulting json object to something like a binary blob that I would just have to reinterpret_cast to use.

[nlohmann]

No, there is no way to read a JSON file without parsing it. But you can similarly pipe to a std::ofstream, see https://json.nlohmann.me/api/basic_json/operator_ltlt/.

[nlohmann]

I understand, but this is not possible.

[Tom-Evers]

I'll let you know when I've built something for it... As it stands now, parsing a json file that contains my GUI structure takes up 40% of the startup time :(

[nlohmann]

Release mode?

[Tom-Evers]

No, debug mode, but the slow startup is kind of a big problem during development right now

[nlohmann]

Oh. How large is the JSON then? Is it deeply nested or contains of really long arrays/objects?